39^ CONNECTICUT EXPERIMENT STATION REPORT, IQI2. 



Sound* and its contributory rivers, and was soon followed in 

 all these regions by the outbreak of chestnut blight. 



Merkel (32), just about a year after the blight was first noticed 

 by him, states that 98 per cent, of the trees were then affected, 

 and adds: "The disease was noticed with equal frequency 

 upon young specimens in the nursery, upon sprouts that had 

 sprung from stumps of trees cut down the previous year, on 

 young vigorous trees thirty to forty feet high standing in deep, 

 rich soil, and also upon the few survivors of the primeval 

 forest with trunks twelve to fourteen feet in circumference." 

 Such a destructive and indiscriminate attack in a single year is 

 not the history of the blight in the later infected regions. To 

 the writer it leads to but one conclusion, namely, that in those 

 regions where the blight first appeared and was most severe 

 the trees had suffered severely from winter injury, as this is 

 the only agent we know of that acts in such a quick and thorough 

 manner. 



Drought Injury. There are a number of observers, like Met- 

 calf and Collins, who claim that lack of moisture as affecting 

 the vigor of the chestnut has nothing whatever to do with the 

 spread of the blight, but that, on the other hand, it should show 

 greater progress in moist seasons, since these favor spore 

 development and infection. This idea is also expressed in the 

 following statement by Murrill (46) : "Dry summers and 

 otherwise unfavorable conditions may delay the progress of 

 the disease a few years, but not very long." If the fungus 

 were a strictly parasitic species, the condition of whose host 

 made no difference in its virulence, this would be true. The 

 writer, however, holds that the reverse is really the truth, namely, 

 that drought, by weakening the trees, has greatly increased the 

 spread of the disease, and that moist years, while favoring spore 

 production, increase the resistance of the trees, and thereby really 

 lessen infection. 



From 1907 to 1911 Connecticut, at 4 least, had an unusual series 

 of summers, with drought periods that caused serious damage 

 to cultivated crops and forest trees in general. For trees alone, 

 that of 1911 caused the most injury, since it was not only severe 



* Hodson (28) wrote in 1908 : "A favorable feature in the situation is 

 that so far the disease has done most damage in the vicinity of the sea." 



